# Define here the models for your spider middleware
#
# See documentation in:
# https://docs.scrapy.org/en/latest/topics/spider-middleware.html

from scrapy import signals
import re
# useful for handling different item types with a single interface
from itemadapter import is_item, ItemAdapter
from selenium import webdriver
from scrapy.http import HtmlResponse
from selenium.webdriver import ChromeOptions
from scrapy.downloadermiddlewares.retry import RetryMiddleware


class WebDriverMiddleware(RetryMiddleware):  # RetryMiddleware 重试类

    option = ChromeOptions()  # 实例化驱动通信参数
    option.add_experimental_option("prefs", {"profile.managed_default_content_settings.images": 2})  # 不加载图片
    option.add_argument('connection="close"')  # 关闭连接状态
    option.add_argument('--headless')
    option.add_argument('--disable-gpu')
    option.add_experimental_option('excludeSwitches', ['enable-automation'])  # 开发者模式（可不使用）

    def process_request(self, request, spider):
        browser = webdriver.Chrome(options=self.option,executable_path='D:/driver/chromedriver.exe')
        browser.get(request.url)
        data = browser.page_source.encode('utf-8')
        browser.quit()
        return HtmlResponse(request.url, body=data, encoding='utf-8', request=request)

    # TODO 当IP被ban掉之后，返回request，重新请求
    def process_response(self, request, response, spider):
        proxy_error = re.findall('我们的系统检测到您网络中存在异常访问请求', response.text, re.S)
        if proxy_error:
            return self._retry(request, response.body, spider) or response
        else:
            return response

class ImageSpiderMiddleware:
    # Not all methods need to be defined. If a method is not defined,
    # scrapy acts as if the spider middleware does not modify the
    # passed objects.

    @classmethod
    def from_crawler(cls, crawler):
        # This method is used by Scrapy to create your spiders.
        s = cls()
        crawler.signals.connect(s.spider_opened, signal=signals.spider_opened)
        return s

    def process_spider_input(self, response, spider):
        # Called for each response that goes through the spider
        # middleware and into the spider.

        # Should return None or raise an exception.
        return None

    def process_spider_output(self, response, result, spider):
        # Called with the results returned from the Spider, after
        # it has processed the response.

        # Must return an iterable of Request, or item objects.
        for i in result:
            yield i

    def process_spider_exception(self, response, exception, spider):
        # Called when a spider or process_spider_input() method
        # (from other spider middleware) raises an exception.

        # Should return either None or an iterable of Request or item objects.
        pass

    def process_start_requests(self, start_requests, spider):
        # Called with the start requests of the spider, and works
        # similarly to the process_spider_output() method, except
        # that it doesn’t have a response associated.

        # Must return only requests (not items).
        for r in start_requests:
            yield r

    def spider_opened(self, spider):
        spider.logger.info('Spider opened: %s' % spider.name)


class ImageDownloaderMiddleware:
    # Not all methods need to be defined. If a method is not defined,
    # scrapy acts as if the downloader middleware does not modify the
    # passed objects.

    @classmethod
    def from_crawler(cls, crawler):
        # This method is used by Scrapy to create your spiders.
        s = cls()
        crawler.signals.connect(s.spider_opened, signal=signals.spider_opened)
        return s

    def process_request(self, request, spider):
        # Called for each request that goes through the downloader
        # middleware.

        # Must either:
        # - return None: continue processing this request
        # - or return a Response object
        # - or return a Request object
        # - or raise IgnoreRequest: process_exception() methods of
        #   installed downloader middleware will be called
        return None

    def process_response(self, request, response, spider):
        # Called with the response returned from the downloader.

        # Must either;
        # - return a Response object
        # - return a Request object
        # - or raise IgnoreRequest
        return response

    def process_exception(self, request, exception, spider):
        # Called when a download handler or a process_request()
        # (from other downloader middleware) raises an exception.

        # Must either:
        # - return None: continue processing this exception
        # - return a Response object: stops process_exception() chain
        # - return a Request object: stops process_exception() chain
        pass

    def spider_opened(self, spider):
        spider.logger.info('Spider opened: %s' % spider.name)
